The present invention relates to a vehicle adapted for both sailing on water and free flight. The invention is related to sailboats and airplanes, combining features of both types of vehicles with other new features into a vehicle having unique capabilities.
A traditional sailboat has a low level of aerodynamic efficiency, that is, the aerodynamic drag force is a relatively large fraction of the side force developed by the sail. The excess drag is partly induced drag due to tip losses at the top and bottom of the sail, and partly parasite drag due to turbulent flow past the unstreamlined hull and crew. In addition, a typical sailboat has poor hydrodynamic efficiency because of the large drag associated with moving a heavy object through water at a high speed. Consequently, maximum speeds of sailboats are relatively low (less than 35 mph).
By redesigning a sailboat with airplane-like parts, arranged to give a side force, a great improvement in aerodynamic efficiency can be achieved. At the same time, by using aerodynamic lift to support a large part of the vehicle weight, the hydrodynamic drag can be greatly reduced. The result is a vehicle that sails much faster than a conventional sailboat, and has the added capability of performing as an airplane in free flight.